Added first draft of login and tour select page

lib/model/delivery.dart

@@ -0,0 +1,19 @@
+import 'package:app_gaslieferung/model/receipt.dart';
+
+enum PaymentMethod { creditCard, cash }
+
+class Delivery {
+  Receipt receipt;
+
+  DateTime? deliveredAt;
+  DateTime? desiredDeliveryTime;
+  String? driverInformation;
+
+  Delivery({
+    required this.receipt,
+
+    this.desiredDeliveryTime,
+    this.driverInformation,
+    this.deliveredAt
+  });
+}